ABSTRACT
Objective To study the neurotoxic effects of acute exposure of methylmercury at low dose and to provide some experimental data for deeply exploring the early mechanism of neurotoxicity of methylmercury. Methods SD rats were administered with methylmercury chloride by intraperitoneal injection with different doses of 0.05, 0.50 and 5.00 mg/kg and different exposure times of 20 min, 1 h, 4 h, 24 h. Mercury, ACh and AChE contents in rat brains were measured. Results Mercury contents in rat brains significantly increased after 20 min-exposure at both 0.50 and 5.00 mg/kg doses. Significant increase occurred after 4 h exposure at dose of 0.05 mg/kg. ACh and AChE in rat brains significantly changed after 20 min at every dose, showing certain dose-response and time-response relations. Conclusion Changes of ACh and AChE in rat brain after administration of low dose(0.05 mg/kg) and short time(20 min) exposure suggested certain modulation of CNS had been initiated. With the increases of exposure dose and time, methylmercury might begin to accumulate in rat brain and induce the significant changes of ACh and AChE.